3-Bromopyruvate Attenuates Experimental Pulmonary Hypertension via Inhibition of Glycolysis.

Abstract

The shift of metabolism from mitochondrial oxidative phosphorylation to glycolysis and mitochondria binding partner of hexokinase are features common to cancer. These have been seen in pulmonary hypertension (PH) as well. An inhibitor of hexokinase 2 (HK 2), the small molecule 3-bromopyruvate (3-BrPA) is an incredibly powerful and swift-acting anticancer agent. However, whether it could be of potential benefit to PH has still been unknown. Sprague-Dawley rats with monocrotaline (MCT)-induced PH were administered 2 oral doses of 3-BrPA (15 and 30 mg/kg/day, respectively) for 14 days. Hemodynamic parameters were obtained by right heart catheterization. Histopathology, immunohistochemistry, transmission electron microscopy, flow cytometry, and assessments of relative protein expressions were conducted. Compared with MCT treatment, 3-BrPA decreased mean pulmonary arterial pressure and pulmonary vascular resistance, and increased cardiac output. 3-BrPA significantly suppressed proliferation in addition to enhancing apoptosis of pulmonary artery smooth muscle cells, attenuating small pulmonary artery remodeling and right ventricular hypertrophy. Treatment with 3-BrPA markedly reduced the mitochondrial membrane potential and restored mitochondrial structure. Furthermore, 3-BrPA significantly inhibited HK 2 expression but not HK 1. The expression of both pyruvate dehydrogenase kinase and lactate dehydrogenase was decreased whereas that of pyruvate dehydrogenase and cytosolic cytochrome c was upregulated with 3-BrPA administration. This study demonstrates the reversal of PH by 3-BrPA is related to alteration in glycolysis and improved mitochondria function, indicating the "metabolic targeting" as a rational therapeutic strategy for PH.